Wrote simple blender service for rendering models and added to stack

blender_server/Dockerfile

@@ -0,0 +1,15 @@
+FROM golang:alpine AS builder
+WORKDIR /app
+COPY go.mod go.sum* ./
+RUN go mod download
+COPY . .
+RUN CGO_ENABLED=0 GOOS=linux go build -o server ./main.go
+
+FROM alpine:latest
+RUN apk update
+RUN apk add blender
+WORKDIR /root/
+COPY --from=builder /app/server .
+COPY main.py.tmpl .
+EXPOSE 8080
+CMD ["./server"]

blender_server/go.mod

@@ -0,0 +1,3 @@
+module blender_server
+
+go 1.23.3

blender_server/main.go

@@ -0,0 +1,167 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"text/template"
+	"encoding/json"
+	"log"
+	"net/http"
+	"path/filepath"
+)
+
+func main() {
+	http.HandleFunc("/create_model", handleCreateModel)
+
+	port := os.Getenv("PORT")
+	if port == "" {
+		port = "8080"
+	}
+	log.Printf("Server starting on port %s", port)
+	if err := http.ListenAndServe(":"+port, nil); err != nil {
+		log.Fatalf("Failed to start server: %v", err)
+	}
+}
+
+const ModelPath = "./model.stl"
+
+type Request struct {
+	ModelCode string `json:"model_code"`
+}
+
+func handleCreateModel(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	bodyBytes, err := io.ReadAll(r.Body)
+	if err != nil {
+		http.Error(w, "Error reading request body", http.StatusBadRequest)
+		return
+	}
+
+	log.Printf("Received request body (first 100 chars): %s", truncateString(string(bodyBytes), 100))
+
+	// Close the original body and create a new one with the same data
+	r.Body.Close()
+	r.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))
+
+	var req Request
+	err = json.NewDecoder(r.Body).Decode(&req)
+	if err != nil {
+		log.Printf("JSON decode error: %v", err)
+		http.Error(w, fmt.Sprintf("Invalid request body: %v", err), http.StatusBadRequest)
+		return
+	}
+
+	log.Printf("Successfully parsed request: ModelCode (first 50 chars)=%s", truncateString(req.ModelCode, 50))
+
+	absModelPath, err := filepath.Abs(ModelPath)
+	if err != nil {
+		log.Printf("Error getting absolute path: %v", err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	_ = os.Remove(absModelPath)
+
+	model_expression, err := create_stl(req.ModelCode, absModelPath)
+	if err != nil {
+		http.Error(w, fmt.Sprintf("Error parsing templates: %v", err), http.StatusInternalServerError)
+		return
+	}
+
+	log.Printf("Python expression generated (first 100 chars): %s", truncateString(model_expression, 100))
+
+	tmpFile, err := os.CreateTemp("", "blender_*.py")
+	if err != nil {
+		log.Printf("Error creating temp file: %v", err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
+	defer os.Remove(tmpFile.Name())
+
+	_, err = tmpFile.WriteString(model_expression)
+	if err != nil {
+		log.Printf("Error writing to temp file: %v", err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
+	tmpFile.Close()
+
+	cmd := exec.Command("blender", "-b", "--python", tmpFile.Name())
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		log.Printf("Command execution failed: %v, Output: %s", err, string(output))
+		http.Error(w, fmt.Sprintf("Command execution failed: %v", err), http.StatusInternalServerError)
+		return
+	}
+
+	log.Printf("Blender command executed: output (first 200 chars): %s", truncateString(string(output), 200))
+
+	if _, err := os.Stat(absModelPath); os.IsNotExist(err) {
+		log.Printf("Error: STL file was not created at %s", absModelPath)
+		http.Error(w, "Failed to generate STL file", http.StatusInternalServerError)
+		return
+	}
+
+	stlData, err := os.ReadFile(absModelPath)
+	if err != nil {
+		log.Printf("Error reading STL file: %v", err)
+		http.Error(w, "Error reading generated STL file", http.StatusInternalServerError)
+		return
+	}
+
+	log.Printf("STL file read successfully, size: %d bytes", len(stlData))
+
+	w.Header().Set("Content-Type", "application/octet-stream")
+	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filepath.Base(ModelPath)))
+	w.Header().Set("Content-Length", fmt.Sprintf("%d", len(stlData)))
+
+	if _, err := w.Write(stlData); err != nil {
+		log.Printf("Failed to write response: %v", err)
+	} else {
+		log.Printf("STL file sent successfully")
+	}
+}
+
+type ModelTemplateVars struct {
+	ModelCode string
+	Filename  string
+}
+
+func create_stl(model_code string, filename string) (string, error) {
+	t := template.New("main.py.tmpl")
+
+	t, err := t.ParseFiles("main.py.tmpl")
+	if err != nil {
+		fmt.Println("Error parsing templates:", err)
+		return "", err
+	}
+
+	var buf bytes.Buffer
+	data := ModelTemplateVars{
+		ModelCode: model_code,
+		Filename:  filename,
+	}
+
+	err = t.ExecuteTemplate(&buf, "main.py.tmpl", data)
+	if err != nil {
+		fmt.Println("Error executing template:", err)
+		return "", err
+	}
+
+	result := buf.String()
+	return result, nil
+}
+
+func truncateString(s string, maxLen int) string {
+	if len(s) <= maxLen {
+		return s
+	}
+	return s[:maxLen] + "..."
+}

blender_server/main.py.tmpl

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+import bpy  # type: ignore
+
+
+{{.ModelCode}}
+
+
+def guarded_model() -> bpy.types.Object:
+    try:
+        out = model()  # type: ignore
+        if out is None:
+            raise TypeError("Function `model` cannot return type `None`.")
+        return out
+    except NameError:
+        raise NotImplementedError("No function named `model` was provided!")
+
+
+def export_to_stl(obj: bpy.types.Object):
+    """
+    Export a Blender object as an STL binary blob.
+
+    Parameters:
+        obj (bpy.types.Object): The object to export
+
+    Returns:
+        bytes: Binary data of the STL file
+    """
+    import tempfile
+    import os
+
+    # Ensure the object is the only object, is selected, and is active
+    bpy.ops.object.select_all(action="SELECT")
+    obj.select_set(False)
+    bpy.ops.object.delete()
+    obj.select_set(True)
+    bpy.context.view_layer.objects.active = obj
+
+    bpy.ops.wm.stl_export(filepath="{{.Filename}}")
+
+
+def main():
+    export_to_stl(guarded_model())
+
+
+main()